The present invention is related to a high accuracy, safe, and adjustable tool, and in particular, to a tool for preparing a substrate edge of a counter-top to accept a molded apron.
Counter-tops are often fabricated from a substrate laminated with a laminated plastic (e.g., "FORMICA"). The substrate is typically wood, such as plywood, chipboard, or particle board. The laminated plastic (e.g., "FORMICA") is glued to the top and edge surfaces of the substrate and trimmed to achieve flush and uniform edges. Unfortunately, the finished (i.e., exposed) surface of laminated plastics (such as "FORMICA") is quite thin and as a consequence, scratches in the finished surface can not be repaired. A further drawback of a substrate laminated with a laminated plastic (such as "FORMICA") is that edges formed between the laminated plastic (e.g., "FORMICA") on the top surface of the substrate and the laminated plastic (e.g., "FORMICA") on a perpendicular edge surface of the substrate are visually "sharp" and can not be "softened" by routing a beveled edge or a rounded edge larger than the thickness of the laminated plastic (e.g., "FORMICA").
To overcome this drawback, thick solid synthetic products such as "CORIAN" and "SURELL," were introduced. These thick solid synthetic products can be cut, routed, and sanded using conventional power tools. The thick solid material itself provides the finished (i.e., exposed) surfaces. Therefore, scratches in the exposed surfaces of these products can be "sanded out" since these products are made from thick solid material and not a thin laminated finished surface. While these products have become popular, they are quite expensive. The expense of these materials is due, in large part, to their thickness.
To provide a less expensive alternative to the thick solid synthetic products mentioned above, semi-thick solid synthetic products were introduced. An example of a semi-thick solid synthetic product is "NUVEL" which is typically 3/32 of an inch thick. Like the thick solid synthetic products, with these semi-thick solid synthetic products, the material itself provides the finished (i.e., exposed) surface. Since scratches received by counter-tops are typically less than 3/32 of an inch deep, scratches can be "sanded out" of the semi-thick solid synthetic products in the same way that scratches are "sanded out" from the thick solid synthetic products. However, similar to the laminated plastics (such as "FORMICA"), the semi-thick solid synthetic products must be glued to a strong and rigid substrate surface, for example, wood such as plywood, chip board, or particle board. Consequently, an apron molding is needed to cover edge surfaces of the substrate and to simulate the look of the more expensive thick solid plastic products. The apron molding is typically fabricated from the same synthetic material as the thick solid synthetic products such as "CORIAN" or "SURELL." The apron molding should align with an end of a semi-thick solid synthetic product bonded to a top surface of the substrate. Further, the apron molding should be sufficiently thick so that edges formed by the semi-thick solid synthetic product and the apron molding may be softened by routing a beveled edge or a curved edge. Flat-backed apron moldings are inadequate for such applications because alignment with the end of the semi-thick solid synthetic product bonded to the top surface of the substrate is not assured. Further, a glue bond between the apron molding and an edge surface of the substrate, by itself, may provide an insufficient bond when the apron molding is subjected to the cutting operations necessary for beveling or rounding the edges discussed above.
In view of the above drawbacks of flat-backed apron moldings, apron moldings having two or more perpendicular appendages were created. By properly preparing the edge surface of the substrate, the perpendicular appendages of the apron molding can be held to the substrate edge with a friction fit in addition to an adhesive bond. Unfortunately, preparing the substrate for such an apron molding presents several difficulties.
First, the substrate must be cut to form two or more channels and/or rabbets to accept the two or more perpendicular appendages of the apron molding. The distance between the channels or rabbets must closely match the distance between the perpendicular appendages of the apron molding so that a tight friction fit is assured. This distance must be maintained even after the tool for preparing the substrate edge wears and is sharpened.
The tool for preparing the substrate edge for the apron molding should also be able to simultaneously trim the edge of the semi-thick solid synthetic material so that it is flush with the finished (i.e., exposed) surface of the apron molding.
If preparing the substrate edge involves providing rabbets, the tool for preparing the substrate should be able to provide a rabbet at the top of the substrate without damaging or cracking the semi-thick plastic material and should be able to provide a rabbet at the bottom of even thick substrates.
Providing bevels in the edge of the substrate at areas adjacent to the channels and/or rabbets is desirable because this permits the perpendicular appendages of the apron molding to be more easily positioned at, and forced into, the channels and/or rabbets.
Lastly, the tool used for preparing the substrate edge must safe, even when the tool operates at rotational velocities of up to 16,000 rpm.